Data analysis revealed high immunoreactivity in 93.3% of tumor tissues (14/15, IHC score ≥ 8) but low expression of HDAC9 in 73.3% of adjacent normal tissues (11/15, IHC score ≤ 4), indicating an increase in HDAC9 expression in cancerous tissues (Fig. 4d, e). This evidence concerns the gene HDAC9 and neoplasm.